1.Easy
Practice exercise (made-up values, not clinical guidance). In a patient, vancomycin has an elimination half-life of 9 h. Find the elimination rate constant k in h⁻¹.
t½ = 9 h
k = h⁻¹
Clinical pharmacokinetics worksheet with answers
2.Easy
Practice exercise (made-up values, not clinical guidance). A patient who weighs 95 kg needs a loading dose of vancomycin to reach a level of 20 mg/L straight away. The volume of distribution is 0.7 L/kg. Find the loading dose LD in mg.
95 kgVd = 0.7 L/kgC = 20 mg/L
LD = mg
3.Medium
Practice exercise (made-up values, not clinical guidance). An 87 kg patient receives a theophylline infusion. The clearance is 0.04 L/kg/h. What infusion rate R in mg/h gives a steady-state level of 12 mg/L?
87 kgCL = 0.04 L/kg/hCss = 12 mg/L
R = mg/h
4.Medium
Practice exercise (made-up values, not clinical guidance). After an IV dose of tobramycin, the level is 10 mg/L at 1 h and 5.7 mg/L at 3 h. Assume first-order elimination. Find the half-life t½.
C1 = 10 mg/L (1 h)C2 = 5.7 mg/L (3 h)
t½ = h
5.Hard
Practice exercise (made-up values, not clinical guidance). A vancomycin infusion runs at 100 mg/h with no loading dose. The patient's clearance is 4 L/h and the half-life is 6 h. What is the level C after 11 h?
R = 100 mg/hCL = 4 L/ht½ = 6 ht = 11 h
C = mg/L
6.Hard
Practice exercise (made-up values, not clinical guidance). A patient's tobramycin half-life is 3.5 h. The target is a peak of 7 mg/L and a trough of 0.5 mg/L. Assuming rapid IV doses and first-order elimination, what dosing interval τ lets the level fall from the peak to the trough? Round to one decimal place.
t½ = 3.5 hCpeak = 7 mg/LCtrough = 0.5 mg/L
τ = h
Answer key
- 1. k = 0.07702 h⁻¹
- 2. LD = 1330 mg
- 3. R = 41.76 mg/h
- 4. t½ = 2.466 h
- 5. C = 17.98 mg/L
- 6. τ = 13.3 h
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